Common types of solar collectors are often in the form of an independent unit either mounted on a ground or roof support with a transparent cover overlying a heat pan carrying a generally serpentine conduit for water to be heated by the sun's rays, for example as shown in U.S. Pat. Nos. 3,910,490, and 1,338,644. In the first noted patent, FIG. 2 shows an "asphalt roof collector" and swimming pool water simply flows over the outer surface of the roof rather than through a fluid carrying conduit embedded in the asphalt. Another patent showing a roof collector in which water simply flows across the outer surface of the roof is U.S. Pat. No. 3,254,701. An interesting patent is U.S. Pat. No. 3,077,190, in which the outer or upper surface of what appears to be a path is in fact a glass plate 30 and this patent has nothing to do with paving or any form of a roadway. Another patent of interest, because of its FIG. 6, is U.S. Pat. No. 3,339,629, but is actually far removed from the subject matter of the present invention. Still another patent utilizing a roof for a solar generator is U.S. Pat. No. 3,087,309, in which a solar generator 3 includes a plurality of small solar generators 4 each utilizing a silicon strip and a layer of boron and sensitive to light for generating electricity.
Large areas of asphalt shown in U.S. Pat. Nos. 2,268,320, and 2,371,629, are heated by the sun for generating thermal currents to aid sail-planes in soaring, and the like. In the first of these patents FIG. 6 shows imbedded steam pipes for aiding in heating the asphalt and FIG. 7 shows electric heating thereof.
An ice skating rink with tubes carrying refrigerant is shown in FIG. 6 of U.S. Pat. No. 2,457,619. Use of embedded tubes in an ice rink installation is well known, another example being shown in U.S. Pat. No. 3,878,694, in which heat provided from a refrigerant is utilized to provide a "thermal equilibrium free of the danger of deep frost penetration", for a more structurally sound installation. While ice rink installations often have a refrigerant carrying embedded conduit in the ice supporting base of the rink and the refrigerant leaving the conduit in a relatively heated state, installations of this type are far removed from solar collectors and often have their ice supporting surface painted a light color, as white in outdoor rinks exposed to the sun's rays. Installations of this type are not concerned with prolonging the life of paving by reducing its temperature as the paving remains at a low temperature when cooling refrigerant is circulated thereto.
A solar collector having embedded conduits is shown in U.S. Pat. No. 3,815,574 the conduit being embedded in sand in a box with a black top layer on the sand, and with a glass cover as in typical collectors. A "Solar Air Moving System" is shown in U.S. Pat. No. 3,436,908 in which an embedded air carrying tube is open at upper and lower ends and as the tube is heated by the sun's rays air moves upwardly through the tube to drive a fan generator unit.
Other U.S. Pat. Nos. which appear to be of substantially less interest are: 2,138,689; 2,257,524; 2,277,311; 2,529,154; 3,129,703; 3,377,462; 3,509,716; 3,680,449; 3,780,262; 3,893,443; and 3,908,631.
While it is common practice to construct a flat roof so that it may be flooded with water to aid in cooling a building; and as shown in some of the previously noted patents, water may flow over the surface of a pitched roof for heating the water and somewhat cooling the roof, but the concept of cooling roofing by passing a cooling fluid through conduits embedded in the roofing is apparently lacking in the prior art. Such embedded conduits have a further advantage in carrying a fluid for heating the roof and thereby removing accumulations of snow and ice. Embedded conduits further permit providing a more attractive outer surface on the roof without the continuous wearing away which would occur when water or some other fluid continuously flows across the outer surface of the roof.
It is of course common practice to run cooling water across a roadway such as a patio, or a concrete seating area of an amphitheater, but this practice increases the humidity and often results in objectionable puddles.
In surface cooling of both roofing and roadways by flowing water there across, the heat taken up by the flowing water is usually unwanted and wasted, although one of the previously noted patents, U.S. Pat. No. 3,910,490, does show utilizing the heated water for a useful purpose, but as suggested in this patent the surface of the roof would be unique if not unsightly.